Orthotic or prosthetic joint device, and method for controlling same

ABSTRACT

The invention relates to an orthotic or prosthetic joint device with an upper part and a lower part arranged in a hinged manner and fastening means for securing the joint device on a user, with at least one hydraulics unit between the upper part and the lower part, which hydraulics unit has a piston that is movable in a housing with an extension chamber and a flexion chamber and that is coupled to the upper part or the lower part, and which hydraulics unit is assigned a pressure supply device with a pump and a pressure accumulator via which the piston, controlled by a control device, is subjected to a pressure, wherein the pump can be operated in generator mode, the pressure accumulator can be coupled drivingly to the pump, and the hydraulic fluid can be conveyed by the pressure accumulator through the pump to the hydraulics unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/412,422, filed Dec. 31, 2014, and entitled “ORTHOTIC OR PROSTHETICJOINT DEVICE, AND METHOD FOR CONTROLLING SAME” “, issued as U.S. Pat.No. 11,096,804, which is a U.S. National Entry and claims priority toPCT International Patent Application No. PCT/EP2013/001868, filed Jun.26, 2013, and entitled “ORTHOTIC OR PROSTHETIC JOINT DEVICE, AND METHODFOR CONTROLLING SAME”, which claims priority to German PatentApplication No. 102012013141, filed Jul. 3, 2012, the entire disclosuresof which are incorporated herein by this reference.

TECHNICAL FIELD

The invention relates to an orthotic or prosthetic joint device with anupper part and a lower part, arranged in an articulated manner thereon,and also fastening devices for securing the joint devices on a user,with at least one hydraulic unit between the upper part and the lowerpart; the hydraulic unit has a piston, which is located in a housing andis coupled to the upper part or the lower part; the hydraulic unit isassigned a pressure providing device, by way of which a pressure isapplied to the piston; and also a method for controlling an orthotic orprosthetic joint device.

BACKGROUND

The aim of orthotic or prosthetic devices is to compensate fordisabilities in the apparatus of locomotion. In the case of patientsthat require orthotic or prosthetic joint devices on a lower extremity,increased concentrational effort and increased expenditure of energy isnecessary, since, during walking, not only the possibly still presentlimbs but also the prosthetic device or orthotic device has to beaccelerated, that is to say has to be moved from a rest position in aforward direction, and decelerated before setting down. In order toproduce a gait that is as natural as possible, dampers are provided inprosthetic devices, assuming various tasks. Apart from standing phasedamping, which provides increased stability of the prosthetic jointduring the standing phase, swinging phase damping is provided, whichavoids swinging into the limit stop without deceleration. The kineticenergy is converted into heat by the damper.

Furthermore, driven prosthetic devices, which actively assist pivotingof the lower part in relation to the upper part, are known from theprior art.

WO 2004/017872 A1 describes a driven prosthesis with a prosthetic kneejoint that is assigned a damping unit. Likewise provided is a linearactuator, which pivots the lower leg shank with respect to the upperpart. The energy is supplied by way of a flexible battery belt. Thelinear motor and the damper are structurally separate from one another.

WO 2006/112774 A1 relates to a combination of an actuated leg prosthesisand a passive leg prosthesis and also a method for executing a movementwith a corresponding prosthesis system. The prosthesis system has amovable joint and a pump, which by way of a valve device can move ahydraulic piston in one direction or the other, so that a flexionmovement or extension movement of the prosthetic knee joint is executed.The pump must produce the entire working pressure for the movement. Thisrequires a great pump output, which in turn requires large pumps, whichhave a large overall volume and require correspondingly large energystorage devices.

SUMMARY

The object of the present invention is to provide an orthotic orprosthetic joint device and a method for controlling the same, whichdevice makes energy-saving operation possible, and consequently a longtime in use with comfortable control, in spite of having a highperformance capability.

This object is achieved according to the invention by a device with thefeatures of the main claim and a method with the features of thealternative independent claim. Advantageous configurations anddevelopments of the invention are presented in the subclaims, thedescription and the figures.

The orthotic or prosthetic joint device with an upper part and a lowerpart, arranged in an articulated manner thereon, and fastening devicesfor securing the joint device in a user, with at least one hydraulicunit between the upper part and the lower part, which hydraulic unit hasa piston, which is movable in a housing and is coupled to the upper partor the lower part and is assigned a pressure providing device with apump and a pressure accumulator, by way of which a pressure is appliedto the piston while being controlled by a control device, provides thatthe pressure accumulator can be coupled to the pump in a driving way.From the pressure accumulator, driving fluid can consequently be fed tothe pump. The operating mode of the pump is in this case controlled byway of the pressures present and required, which are present at thehydraulic unit and the pressure accumulator. How high the respectivelyrequired pressure or volumetric flow is, and when which pressure must bepresent, is controlled by way of sensors, which detect loads, movementvariables and/or positions, in particular angular positions. As aresult, the development of pressure can be influenced by way of thepump.

The pump may be operable in generator mode, so that electrical energycan be generated when there is a surplus of mechanical or kineticenergy, for example when going down an incline.

A development provides that the hydraulic fluid can be fed from thepressure accumulator through the pump to the hydraulic unit. Thepossible feeding of the hydraulic fluid from the pressure accumulatorthrough the pump to the hydraulic unit makes it possible to influencethe flow of the hydraulic fluid and, in the case of a pressure of thepressure accumulator that is too high, bring about a limitation of thepressure by switching over to generator mode.

The hydraulic fluid from the pressure accumulator can be admitted toboth the flexion chamber and the extension chamber, so that the controlof the joint device can take place in all movement situations. Assistingthe flexion and extension is possible, and similarly the deceleration ofmovements or the application of counterforces that go beyond an increasein damping is possible. It has been found that, for controlling orthoticor prosthetic joint devices, relatively large amounts of hydraulic fluidhave to be provided relatively quickly in order to achieve timelyactuation of the respective component. Those phases in which a supply ofenergy or a conversion of energy takes place in the case of a movementare relatively short, but an impulse-like admission of fluid with apressure component is sometimes undesired, so that the impulse has to beattenuated or the impulse characteristic has to be adapted to therespective movement. This may take place by the feeding of the fluidthrough the pump, which can act as a throttle, the energy allowingitself to be converted into electrical energy by the generator mode whenthere is a decrease in the pressure. Nevertheless, large amounts ofpressure fluid can be provided for a short time by the pressureaccumulator, in order to ensure precise control and that the pressurefluid is applied to either the extension side or the flexion side of thepiston. The pump is arranged downstream of the pressure accumulator, inorder to assist or control the pressure accumulator.

In the pressure providing device, the pump may be coupled to thepressure accumulator or the pressure accumulators in such a way that thepressure accumulator or the pressure accumulators can be filled by wayof the pump. As a result, it is possible that the pump does not have toprovide the full performance capability that is necessary for moving thepiston, but

rather the pump can fill the pressure accumulator or the pressureaccumulators continuously, so that a small, lightweight pump thatoperates for a longer time period can be installed. In addition, thepump is used for driving the hydraulic unit, and can be used eitherseparately or in conjunction with the pressure accumulator or thepressure accumulators for driving the hydraulic unit.

The pressure accumulator may be coupled to the hydraulic unitexclusively by way of the pump, so that the hydraulic fluid always hasto pass the pump in order to drive or decelerate the piston. As aresult, the pressure of the hydraulic fluid delivered by the pressureaccumulator can be varied, so that either a pressure increase or apressure decrease can take place in the pump in order to bring thehydraulic fluid that is delivered by the pump to the hydraulic unit tothe required pressure level.

Should it be necessary for pressure to be admitted suddenly to one ofthe chambers or both chambers, for example in a situation involving afall or a failure of the pump, direct coupling of the chambers by way ofa bypass line, with possibly interconnected valves or throttles, may beprovided in order to avoid feedthrough losses and in order to be able totransport the hydraulic fluid more quickly to the chambers.

A variant of the invention provides that the pressure accumulator or thepressure accumulators is/are coupled to the flexion chamber and/or theextension chamber, so that hydraulic fluid passes from the extensionchamber or flexion chamber into the pressure accumulator, so that, whenthere are decelerating movements, for example when going down stairs orwhen going down an incline on a slope, pressurized hydraulic fluid ispumped into the pressure accumulator from the corresponding chamber, sothat the pressure accumulator can be filled not only by the pump, butalso by way of the hydraulic piston itself. The feedthrough to thepressure accumulator may take place by way of the pump, so that, whenthere is a sufficient pressure level in the pressure accumulator, thepump can be operated in generator mode and used for generating power.

The pressure accumulator may be assigned a valve unit, by way of whichthe hydraulic fluid is introduced into the pressure accumulator orremoved from it in a metered and controlled manner. As a result, thekinetic energy can be stored in the form of hydraulic pressure in thepressure accumulator and fed back to the system in a controlled manner.

The joint device may likewise be assigned a device for detecting theabsolute angle, joint angle, the axial force acting on the upper part orlower part, the joint moment and/or the moments of the switching deviceacting on a distal connection component, so that a control in the senseof whether admission of pressure to the extension chamber or to theflexion chamber should take place can take place while taking intoaccount the joint angle, the absolute angle, the effective axial forceor the moments acting on the joint device or the connection parts to thejoint device.

The pump may have a variable delivery volume, which can be adapted tothe pressure in the pressure accumulator, in order that the deliveryvolume can be adapted to the respective fluid requirement. If thepressure in the pressure accumulator rises or falls, this can becompensated by a reduced or increased delivery volume. If only a lowpressure is available in the pressure accumulator, this can becompensated by an increased delivery volume in the direction of thehydraulic cylinder. In order to be able also to increase the pressurewhen discharging from the accumulator, the pump may be designed as apressure increasing pump. It may likewise be provided that the pump isdesigned for being operated in a generator mode, in order that thekinetic energy that cannot be converted directly as a pressure increasein the pressure accumulator is used. In this way, the pressure in thepressure accumulator can be much higher than is required in thehydraulic cylinder. When going down stairs, more energy occurs thanwould have to be supplied, so that the kinetic energy can be converteddirectly into electrical energy. Alternatively or in addition, thepressure accumulator may be operated for a short time with a very highexcess pressure, which is then reduced at a suitable point in time, andpossibly likewise converted into electrical energy.

The joint device is preferably designed as a prosthetic knee joint or anorthotic knee joint, but there are also other possibilities for use, forexample to do with an ankle joint or a foot joint, a hip joint or to dowith prostheses or orthoses on upper extremities.

The hydraulic unit may be designed as rotary hydraulics or as pistonhydraulics, with a linear displacement movement.

A development of the invention provides that there are multiple pressureaccumulators, which provide different pressure volumes and/or pressurelevels. Different walking situations require different types ofassistance. For example, when walking on the level, generally only asmall impulse or minor assistance is required in the case of anextension or flexion, whereas when going up stairs a relatively greatmoment has to be provided for assisting the extension in order toachieve effective assistance. The arrangement of multiple differentpressure accumulators allows the best pressure accumulator in each caseto be selected for the walking situation concerned, so that less energylosses occur and the filling of the pressure accumulators can take placemore quickly than if the maximum pressure and the maximum volume werealways called upon.

The method for controlling an orthotic or prosthetic knee joint devicewith an upper part and a lower part arranged in an articulated mannerthereon and fastening devices for securing the joint device on a user,and also with at least one drive, which provides that, before thebending or stretching, a bending moment or stretching moment that liesbelow the level that leads to bending or stretching is applied to theknee joint device.

It has surprisingly been found that considerable alleviation can beachieved for a patient if, before the actual bending of the knee jointdevice, a moment that assists the bending but is so small that bendingdoes not yet take place is applied. The joint is consequently notactively bent, but rather the level of moment or level of force that isnecessary to achieve bending is reduced. Control over the bendingremains entirely with the patient or the user of the orthotic orprosthetic device. The bending is brought about by the patient when theleg provided with the prosthesis or orthosis is moved. It is not apurely passive joint that is operated by the actuation of the useralone, but rather a semiactive device is achieved, a device that leavesthe initiating moment to the patient, facilitates the initiation itselfand facilitates a bending, in that the moment to be applied for thebending is reduced by a preloading moment and, as bending commences, themoment is maintained for a defined time. The moment is taken over intothe bending.

The same also applies to a stretching moment, which is applied beforethe introduction of a stretching movement or extension movement. Forexample when going up stairs, in the case of active knee joint devices araising up of the patient is brought about by exerting a high amount ofenergy. It has been found that considerable alleviation is achieved fora patient already by an assisting application of stretching moments, thelevel of the stretching moment being below the level that is required toachieve complete raising up of a patient to a higher level or a reversalof movement in the swinging phase.

A development of the method provides that the bending moment that isapplied by a pressure accumulator is reduced when the knee joint deviceis bent or before the knee joint device is bent, so that, after theinitial bending and in the advanced gait cycle when lifting the frontfoot off the ground, the lower leg or the lower leg component isprevented from being bent unwantedly far in such a way as to produce anunnatural gait pattern. Reducing the bending moment directly before orafter the bending of the joint device has the effect of ensuring thatthe bending itself is facilitated; active flexion assistance by thepressure accumulator during the bending, for example during the swingingphase, does not take place.

It is also possible to reduce the reduction of the bending momentdirectly before the bending of the knee joint device. Instead of areduction to zero, the assisting bending moment may continue to exist,but also a reduced level in comparison with the maximum assistingbending moment. Whether the knee joint is bent can be ascertained by wayof a sensor. It may likewise be provided that the bending moment is onlyreduced or switched off after a certain bending. It is thus possible forexample only to switch off the bending moment when there is a bending offor example 4°, or to reduce the assisting bending moment over theincreasing bending angle. The reduction may take place continuously ordiscontinuously. It may be provided that the reduction is reduced downto 0 for example from the beginning of the bending to a predeterminedknee angle, for example of 5° or 6°.

In order not to provide a bending moment below the level of a bendingover a long time period when no bending is to be expected in the normalgait cycle, that is to say during most of the time of the standingphase, it is provided according to the invention that the bending momentis only provided and applied in a limited time period before thebending, which is for example between 5% and 40%, in particular between5% and 20%, of the duration of a gait cycle.

A development of the invention provides that a bending moment orstretching moment of a varying degree is provided in dependence on thewalking situation. In particular in the case of normal walking on thelevel, there is a recurrent, uniform sequence of movements that hasstriking characteristics, on the basis of which the existence or absenceof a walking situation can be detected. For example, walking on thelevel can be detected on the basis of a striking knee angle progression.If such a walking situation is detected, a bending moment adaptedthereto can be provided. If for example going up an incline or going upstairs is detected, instead of or in addition to a bending moment, anextension moment that lies below the level of the actual raising up ofthe patient may be applied before the introduction of the swingingphase, in order to provide alleviation for the patient.

Furthermore, it is possible and intended that a varying bending momentis provided in dependence on the set-up of the prosthesis. In the caseof a secure prosthesis set-up, it is necessary that a higher bendingmoment is applied for the bending of the prosthetic knee joint than inthe case of a dynamic set-up. If a secure prosthesis set-up is chosen,there is for example increased stability in the prosthetic knee jointduring standing, which may be pleasant for the wearer of the prosthesis.If a more secure prosthesis set-up is chosen, this can be made dynamicby an increase in the bending moment adapted thereto, which constitutesa noticeable alleviation during walking.

The bending moment or stretching moment is advantageously only appliedup to a predetermined, ascertained knee angle. The knee angle isdetected by a sensor; the respective moment is reduced or switched offbefore or after reaching the established knee angle.

After the introduction of the bending moment, passive damping may takeplace, in order to prevent the lower leg component from continuing thebending undamped. If at least one hydraulic unit between the upper partand the lower part is used for the drive, which hydraulic unit has apiston that is movable in a housing with an extension chamber and aflexion chamber and is coupled to the upper part or the lower part, andis assigned a pressure providing device with a pump and a pressureaccumulator by way of which pressure is applied to the piston whilebeing controlled by a control device, it is likewise possible that thepump is operated in generator mode in order to recover the consumedenergy for providing the moment and store it in a pressure accumulator.

Furthermore, it is possible that the pump is operated in generator modein order to convert kinetic energy into electrical energy, which canthen be stored and used at a later point in time. Operating the pump ingenerator mode may also be used as a limitation of the pressure, so thatthe hydraulic fluid cannot get into the pressure accumulator without areduction of the pressure. As a result, controlled filling with pressurelimitation, while at the same time utilizing the entire kinetic energy,is possible when going down an incline.

A reduction of the stretching moment may be initiated before reachingthe stretching limit stop, in order to prevent the lower leg fromentering the stretching limit stop without being decelerated and withthe assistance of the pressure providing device.

In the case of alternating climbing of stairs, the pressure providingdevice can apply the stretching moment in such a way that the resultantforce vector is kept ahead of the pivot axis of the knee joint. Theapplication of a stretching moment when going up stairs assists theuser. It is in this case advantageous if the force vector is kept justahead of the pivot axis or the pivot point of the knee joint, so thatbending cannot take place in the stretching phase when going up stairs.

In the standing phase, the pressure providing device may actively keepthe knee joint stretched by a moment, in order to prevent or hinderbending and increase the standing stability for the user.

The pressure providing device may increase the stretching moment in theinitial swinging phase until the maximum bending angle is reached andmaintain this until there is a reversal of movement, the bending momentbeing reduced again when there is a decreasing bending angle. Thepressure providing device in this case acts like an extension assistspring, which counteracts a bending movement until the maximum bendingangle is reached, and which releases the energy absorbed during thebending again in the stretching phase, the pressure providing devicereducing the bending moment in the stretching movement as the stretchingincreases. Active extension assistance in the swinging phase ispossible, but not necessarily provided.

Apart from a hydraulic or pneumatic drive by way of a pump, possiblywith at least one pressure accumulator, a direct drive by way of anelectric motor or other actuating assistance, for example apiezoelectric drive, may also be provided in order to apply a moment bywhich a bending or stretching of the joint device can be assisted.Applying a moment of a magnitude below an active movement has the effectthat the user of the knee joint device retains full control over theinitiation of the movement, the execution of the movement and the endingof the movement, which leads to greater stability during use. The energyor the moment advantageously continues to be supplied even after thebeginning of the movement, in order to facilitate the execution of themovement; in this case, the energy can be supplied at an unreduced orreduced level. Before the end of the movement, the excess energy isconverted by damping, in order not to execute the bending too far or notto allow the joint to enter the stretching limit stop without beingdecelerated in the event of stretching. The invention is advantageous inparticular in the case of slow walking and in the case of prosthesiswearers with short upper leg stumps. The invention reduces the forcesoccurring on the shank and provides a harmonious gait pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are explained in more detailbelow on the basis of the accompanying figures, in which:

FIG. 1 shows a schematic representation of a joint device;

FIG. 2 shows a schematic representation of a hydraulic unit not coveredby the invention;

FIG. 3 shows a timing diagram for walking assistance;

FIG. 4 shows a timing diagram for active extension assistance;

FIG. 5 shows a timing diagram for going up stairs;

FIG. 5a shows a variant of the timing diagram for going up stairs;

FIG. 6 shows a variant of the circuit arrangement;

FIG. 7 shows a further variant of the circuit arrangement;

FIG. 8 shows a variant of the circuit arrangement as shown in FIG. 7;

FIGS. 9 to 12 show control sequences for various walking situations; and

FIG. 13 shows a timing diagram for bending and stretching assistance.

DETAILED DESCRIPTION

In FIG. 1, an orthotic joint device 1 is shown as part of a legorthosis. The joint device 1 has an upper part 2 and a lower partarranged in an articulated manner thereon. Arranged on the upper part 2and the lower part 3 are fastening devices 4, 5, which are formed ascollars or sleeves. In the exemplary embodiment shown, the collars andsleeves are fixed to the upper leg and the lower leg of the user of theorthosis. The upper part 2 is mounted pivotably in relation to the lowerpart 3 about a pivot axis 6. Arranged on the lower part 3 is a footpart, on which sensors 7, 8 may be provided in order to ascertain theposition of the lower part 3, the forces or moments acting thereupon orvelocities. Arranged between the upper part 2 and the lower part 3 is ahydraulic unit 10, which is described in more detail below. Arranged inthe hydraulic unit 10 is a piston rod 13, by way of which a displacementof the upper part 2 in relation to the lower part 3 about the pivot axis6 is brought about. A foot part 9 is connected to the lower end of thelower part 3, in order to be able to receive a foot. Instead of anorthosis, the invention can also be realized with a prosthesis, in thecase of which the fastening devices are fastened to a prosthetic sock onthe upper part, while further prosthetic components, for example a lowerleg shank and a prosthetic foot, are arranged on the lower part of thejoint device. Corresponding arrangements may be provided and formed forjoint devices on hips or upper extremities.

To assist the respective movement, that is to say the bending andstretching movement, a drive by way of which the respective movement isexecuted, initiated or assisted is provided in the hydraulic unit.

In FIG. 2, a schematic representation of the hydraulic unit 10 withadditional components is shown. The hydraulic unit 10 has a housing 11with a piston 12, which is mounted movably thereon and is connected tothe joint device by way of a piston rod 13. The housing 11 is coupled tothe other component respectively of the joint device 1. In the housing11, an extension chamber 14 is separated from a flexion chamber 15 bythe piston 12. An oil reservoir 16 is connected to the extension chamber14 and the flexion chamber 15 by way of corresponding lines and checkvalves 17, 18.

The hydraulic unit 10 is assigned a pressure providing device 20, bywhich the hydraulic system of the hydraulic unit 10 is supplied withhydraulic fluid. A hydraulic pump 21, which is driven by a motor 22,supplies the hydraulic unit 10 with pressurized hydraulic fluid.Likewise provided is a pressure accumulator 23, which likewiseintroduces pressurized hydraulic fluid into the hydraulic system.

The pressure providing device 20 is connected to the hydraulic unit 10by way of a switching device 60 in the form of a switching valve. Theswitching device 60 of the embodiment shown can be switched into threepositions, so that three different flow progressions can be realized,explained in more detail later.

Arranged between the switching device 60 and the hydraulic unit 10 areadjustable valves 40, 50, by way of which the extension damping and theflexion damping can be set. In order to drive the hydraulic unit 10, itis advisable to keep the respective dampings as small as possible, inorder that less flow losses occur. The extension damping is set by wayof the extension valve 40; the flexion damping is set by way of theflexion valve 50. It is possible by way of motors either to variablyrestrict the fluid flow or to shut it off entirely.

Pressure sensors 71, 72, 73 are provided, in order to set the valves 40,50 in dependence on the existing pressures and the desired movements ordampings.

The switching position C shown is intended for passive movement damping,in which the pressure providing device 20 is separated from thehydraulic device 10. Extension damping and flexion damping take place byway of a setting of the respective valves 40, 50; the position of theswitching device is chosen such that driving by the pressure providingdevice 20 is not possible. If a flexion movement is carried out, thepiston 12 is forced downward. The hydraulic fluid flows through theflexion valve 50. The fluid flows out of the extension chamber 14through the flexion valve 50 by way of the reservoir 16 back into theflexion chamber 15. On account of the reduction in the volume that canflow back, occurring due to the piston rod 13, the level in the oilreservoir 16 increases; since there is no assistance by the pump 21 orthe pressure accumulator 23, this is a case of passive flexion.

Passive extension takes place in the event of a reversal of themovement, when the piston 12 moves upward and the hydraulic fluid out ofthe flexion chamber 15 through the extension valve 40 in the flowcircuit through the switching device 60, hydraulic fluid additionallyflowing into the extension chamber 14 out of the reservoir 16 of thehydraulic device 10.

In FIG. 3, three diagrams over time are shown. The upper diagram showsthe knee angle KA and the ankle moment AM over time during normalwalking on the level. The middle diagram shows the flexion damping FDand the extension damping ED over time during normal walking; the lowerdiagram shows the valve position VP at the respective point in time. Thediagrams are shown for the configuration of the joint device as aprosthetic knee joint. The diagrams begin at the point in time at whichthe heel sets down, that is to say at the point in time of what is knownas the “heel strike”. The knee angle KA is 180°; the ankle moment AMacts in the direction of the plantar, and consequently runs under thehorizontal line. The flexion damping FD is high, the extension dampingED low, up to the point in time at which the ankle moment AM becomespositive. Then the extension damping is raised approximately up to thelevel of the flexion damping FD and stays there until there is renewedforward swinging. The flexion damping FD remains high up to the point intime of the lifting off of the front foot, known as “toe off”. Then theflexion damping FD is lowered, in order to make backward swinging of thelower leg possible. The flexion damping remains low until shortly beforethe flexion maximum, and is increased again just before reaching theflexion maximum, that is to say the lowest knee angle KA, in order onthe one hand to decelerate the flexion movement and on the other hand toobtain as quickly as possible maximum security against unwantedbuckling. At the same time, the extension damping ED is reduced, inorder to make the most rapid possible forward movement of the lower legand of the prosthetic foot possible. During the standing phase, thevalve position VP is in the position C, in which passive flexion takesplace. Shortly before the beginning of the flexion maximum, theswitching device 60 is moved into the position A, in order to provideflexion assistance. The bending assistance is configured as soon as acertain knee angle is reached. Controlled extension damping ED ensuresavoidance of what is known as “heel rising”. The active bendingassistance is detected on the basis of the progression of the anklemoment AM.

In order to ensure precise control of the hydraulic unit 10 with thevalves 40, 50 and the switching device 60, sensors which monitor theindividual components are provided. Apart from a knee angle sensor andan ankle moment sensor, axial force sensors may also be provided. Thecontrol may take place for example by observing the knee angle velocity.At a point of inflection of the knee angle velocity, active flexionassistance with the valve position A is activated for a certain timeperiod. The flexion valve 50 is set to a low value and, when a definedjoint angle is exceeded, the assistance is switched off and theswitching device is displaced into the position C.

A variant of the control in which the assistance is constituted byactive extension assistance is shown in FIG. 4. Until lifting off of thefoot, which can be detected from the ankle moment AM, the controlproceeds in the way shown in FIG. 3. Instead of again moving into theposition C for the switching device 60 after the lifting off, the valveposition B is assumed and the extension damping ED increased. In thevalve position B of the switching device 60, the extension is assisted,that is to say that the knee angle velocity is reduced and the pivotingdirection reversed. For smooth switching on of the extension assistance,the extension valve 40 may be closed and opened again at suitable pointsin time. Smooth switching off of the extension assistance is achieved byclosing the flexion valve 50.

In FIG. 5, the diagrams for going up stairs are recorded. There is noankle moment. After the raising of the foot, the knee angle KA isreduced. In order to facilitate this, the extension damping ED isreduced; the switching device 60 moves into the position A, in order tobring about flexion assistance. The flexion damping FD continues toremain low. The extension damping ED is likewise reduced for the timeperiod of the active flexion. Subsequently, the switching device 60 ismoved into the position C, in order to achieve passive flexion withdeceleration of the flexion movement, until the knee angle KA isminimal. Finally, the switching device 60 is moved into the valveposition B, by which active extension is achieved, so that theassistance by the pressure providing device 20 can be made active. Forthe duration of the switching of the switching device 60, the extensiondamping ED is increased again; in the valve position B, in which activestretching is assisted, the extension damping ED is reduced, in order toensure the full effectiveness of the assistance. The flexion damping FDis slowly increased, in dependence on the knee angle KA, during theraising of the patient, whereby the assisting moment becomes smaller anda hard strike against the extension limit stop is avoided. In addition,with an almost stretched-out knee joint, the extension damping ED isincreased, in order likewise to dampen a hard strike.

In FIG. 5a , a variant of the timing diagram according to FIG. 5 isshown. The control device detects the situation that a step is to beclimbed. Starting from the position C, as from a defined knee angle theswitching device 60 is moved into the position A, in order to achieveactive bending assistance. The patient is thereby provided withassistance in bending the prosthetic leg for the step, in order that theprosthetic foot can swing backward in order not to be caught on thelower edge of a step on stairs. In order to ensure the effectiveness ofthe active bending assistance, the flexion damping FD is reduced. Theextension damping remains at the high starting level.

As from a defined target angle of the knee angle KA, the flexionassistance is switched off and the switching device 60 returns to theposition C. The flexion damping FD and the extension damping ED remainunchanged. Shortly before reaching the maximum knee angle, the flexiondamping is increased, in order to limit the maximum knee angle KA. Afterreaching the maximum flexion angle and the setting down of the foot, theextension assistance is activated and the switching device 60 is movedinto the valve position B. At the same time, the extension damping ED isreduced, in order to ensure full assistance for the lifting movement.The flexion damping is left at a high level, for example in order toprevent the patient from falling back. When raising up the patient, theextension damping ED is slowly increased in dependence on the knee angleKA, in order to reduce the assisting moment by the pump 21 or thepressure accumulator 23 and avoid a hard abutment against the extensionlimit stop. After reaching the maximum stretching angle, the assistanceis switched off and the valve position B is switched on.

In FIG. 6, a variant of the active flexion assistance is shown. Thehydraulic unit 10 and also the switching device 60 correspondsubstantially to those of FIG. 2. The pressure providing device 20,however, is coupled to the other components in a different way. The pump21 is designed as a pump that can deliver in both directions, so thatthe pressure accumulator 23 can also charge. The pressure accumulator 23is connected to the pump 21 by a branch line. In this way it is possiblethat a separate admission of pressure to the pressure accumulator 23 isperformed. If the pressure accumulator 23 is discharged, that is to sayhydraulic fluid is delivered from the pressure accumulator 23 in thedirection of the hydraulic unit 10, the pump 21 can additionallyincrease the pressure by the motor. In this case, it is possible torealize two different pressures, since flexion assistance generallyrequires less pressure than extension assistance. In addition, it ispossible to use the pump 21 as a generator. If the pressure in thepressure accumulator 23 is much higher than is required within thehydraulic cylinder of the hydraulic unit 10, the pump 21 can be operatedin a generator mode, in order to bring about a reduction in pressure andat the same time convert part of the hydraulic energy into electricalenergy. The hydraulic energy would otherwise be lost at the respectivevalves 40, 50, since it is intended that the pressure is always switchedon smoothly. By controlling the release of generator energy, it ispossible to work with variable differences in pressure, whereby the lostpower and the conversion of the pressure energy into heat can beminimized.

In addition, it is possible with the circuit according to FIG. 6 thatthe pressure in the accumulator 23 can be significantly increasedwithout leading to increased losses at the valves 40, 50. Theaccumulator 23 can consequently store more energy from the movements ofthe joint device. When the hydraulic fluid is fed through from thepressure accumulator 23 to the hydraulic unit, the pump 21 can beoperated in generator mode, in order to make an adaptation of thedesired hydraulic pressure possible. The reduction of the pressure takesplace by conversion into electrical energy, which can be stored and usedfor operating the pump 21. As long as no active assistance is necessaryfor the extension movement, this position of the control device 60 canalso be used for admitting the hydraulic fluid to the pressureaccumulator 23. For this purpose, the pressure in the pressureaccumulator 23 is measured by way of the pressure sensor 22; at the sametime, the pressure on the hydraulic cylinder 11 is measured at theoutlet of the flexion chamber 15. The pressure sensor 72 indicateswhether there is a difference in pressure between the pressureaccumulator 23 and the flexion chamber 15. The flexion valve 40 is setin dependence on the difference in pressure. If there is no pressure inthe pressure accumulator 23, the user of a prosthesis would notexperience any resistance when the flexion valve 40 is opened completelyand would fall. The flexion valve 40 is therefore switched in dependenceon the pressures in such a way that the user of the joint device alwaysfeels the same resistance when going down stairs. Something similarapplies when going down an incline on a slope. The pressure accumulator23 charges further with every step down an incline, and pressure isthereby admitted to it.

As a further option, be provided, one pressures, accumulator may beprovided, one that is designed for very high pressures, higher thanthose pressures that the pressure accumulator 23 requires for normaloperation of the joint device. The additional accumulator can be chargedto a very high level by going down an incline or going down stairs, sothat the energy storage potential increases. There is the possibilitythat the pump 21 is thereby operated as a pneumatic motor, so thatelectrical energy can be generated in generator mode. The additionalaccumulator could also be discharged into the pressure accumulator 23 ina controlled manner, in order to create pressure reserves.

In FIG. 7, a variant of FIG. 6 is shown, a variant providing thatbetween the pump 21 or the generator and the pressure accumulator 23there is arranged a switching valve 28, with which it is possible todecouple the pressure accumulator 23 from the other components. As aresult, it is possible to operate the pump 21 independently of thepressure accumulator 23. Provided for this purpose is a further checkvalve 29, which is arranged parallel to the already existing check valve24. Both check valves 24, 29 prevent hydraulic fluid from beingdelivered from the pump 21 into the reservoir 16.

In FIG. 8, a variant of the embodiment according to FIG. 7 is shown. Theembodiment according to FIG. 8 provides that a switching valve device290 is arranged parallel to the check valve 29 in the hydraulic line.This valve device 290 makes it possible to bypass the check valve 29when it is in the switching position A. This switching position isshown. In the switching position B of the valve device 290, the bypassis shut off, so that hydraulic fluid cannot flow through the check valve29 when there is a corresponding pressure gradient at the valve 29. Thisadditional valve device 290 serves the purpose that, when there is afilled pressure accumulator 23, an oil flow enforced by a bending of theknee can be used for generating power by way of the pump 21 in agenerator mode. For this purpose, the valve devices 290, 28, 60 shouldbe moved into the corresponding positions, so that the pump 21 can bedriven by the hydraulic fluid in generator mode during the flexion. Thegenerator mode has the effect that possibly additional flexion dampingis achieved by the conversion of the mechanical and hydraulic energyinto electrical energy.

In FIG. 9, the position of the individual valves or control devices andtheir changes over the progression of a step are shown in tabular form.Above the table, a step cycle for walking on the level is shown. Theusual knee angle KA runs between approximately 180° in themaximum-stretched position and about 120° in the maximum-flexedposition. A gait cycle can be divided into multiple phases, the mostimportant division taking place between the standing phase and theswinging phase. Shown is the progression of the knee angle, beginningwith the heel strike, that is to say the setting down of a prostheticfoot joint, which is followed by a standing phase flexion. After thefirst contact with the ground, in which the knee joint is in a stableposition, the knee joint is bent by the loading due to the body weight.The flexion immediately following the loading damps the impulse due tothe ground contact. The initial ground contact and the loading responsetake place in the time periods 1 to 4. Subsequently, an extension of theknee joint is initiated, in order to achieve improved stability.

Subsequently, the extension is completed. These are the mid and terminalstanding phases in the sixth time period. There is subsequently apassive flexion of the knee joint, in what is known as the forwardswinging phase 7. At the end of the forward swinging phase 7, what isknown as the “toe off” takes place, that is to say the lifting of thefoot off the ground, in order that the leg can swing forward. In theinitial swinging phase, the maximum flexion is then subsequentlyreached; in the mid swinging phase 9, the swinging 20 forward of the legis reached and, in the terminal swinging phase, the extension of theknee joint is pursued, in order to reach the maximum knee angle andcarry out the preparation for the standing phase.

In the table presented below this sequence of movements, the individualelements of the hydraulic circuit of the joint device are shown for thesituation with active extension assistance and without active extensionassistance. Up until the terminal standing 30 phase, the switchingdevice 60 is arranged in the middle position C; for the terminalstanding phase up to the maximum flexion, it is brought into the valveposition A, in order to make assistance possible during the initiationof bending. After reaching the maximum flexion, without theextension-assisting function, that is to say extension assistance,assistance by a pressure accumulator 23 or the pump 21 is switched offagain. In the case of extension assistance, after reaching the maximumflexion switching into the valve position B takes place, in order toachieve extension assistance.

The extension valve 40 remains predominantly closed during the standingphase. The extension valve only opens at the beginning of the terminalstanding phase, remains substantially open during the entire flexionphase and the extension valve is only closed again during the terminalswinging phase, in order to avoid a hard strike against the extensionlimit stop. The high extension damping during the standing phaseprevents a hard strike in the extension during the standing phaseextension.

The flexion valve 50 is initially predominantly closed, in order todampen standing phase bending. After the standing phase extension, theflexion damping is reduced, in order to make bending possible. Beforethe initiation of bending, the flexion damping is reduced to the maximumextent, since here the knee joint is kept up against the limit stop bythe ground reaction forces. Without extension assistance, the flexiondamping is increased in the swinging phase in order to avoidover-swinging of the prosthetic foot and what is known as “heel rising”.The flexion damping remains at a high level to allow stumbling to beaverted. The flexion valve with the extension-assisting function doesnot provide any increase in the damping during the flexion phase because“heel rising” does not have to be avoided here, since this is broughtabout by the activation of the extension assistance. The damping in thedirection of flexion remains low for longer in comparison with thedamping without an extension-assisting function in order to makeextension assistance possible.

Subsequently, the flexion damping is increased again, in order to allowstumbling to be averted.

For the variant according to FIG. 8 with the valves 290 and 28, it isprovided that the valve 290 remains closed, in order not to undergo anylosses during the assistance or charging of an accumulator. At the endof the terminal swinging phase, the valve can be opened, in order topass the oil flow through the pump 21 in generator mode, and therebyconvert the mechanical energy into electrical energy. The valve 28 isonly closed during the terminal swinging phase, in order when there is afilled accumulator 23 to use an enforced oil flow for generating powerby way of the generator mode of the pump 21.

FIG. 10 shows the circuit arrangement when going steeply up an incline.It is advisable to work here with extension assistance. Up until theterminal standing phase, the valve 60 is in the position B, in order toensure extension assistance, in order that the patient can climb a stepof stairs more easily or can go up a sloping ramp more easily. Flexionassistance is provided in the initiation of bending after the toe off;extension assistance is provided in the terminal swinging phase. Theextension valve 40 initially remains substantially open, in order toensure low damping in the direction of extension, in order that theextension assistance is effective to the maximum extent. Before reachingthe stretching limit stop, closing of the extension valve 40, andconsequently increasing of the extension damping, is necessary in orderto avoid a hard strike against the extension limit stop. At theswitching times of the switching valve 60, brief closing of theextension valve may be appropriate in order to avoid hard impacts;alternatively, the flexion valve 50 may be briefly closed at thesepoints in time. Otherwise, the flexion valve 50 is substantially openover the entire movement time period, in order to make minimal dampingand maximum assistance possible.

In FIG. 11, a diagram for going steeply down an incline with theextension-assisting function is shown. Over the entire standing phase,the switching valve remains in the position C; no extension assistanceor flexion assistance takes place. Only in the initial swinging phase isthe position B assumed, in order to achieve flexion assistance. Theextension valve is closed in the standing phase, or has a high degree ofdamping, in order to ensure a high degree of extension damping whenthere is no longer a steep downward incline. After reaching the maximumflexion, the extension damping is reduced; in order to make theextension possible, the valve 40 is consequently opened. At the end ofthe swinging phase, the extension is increased again, in order to avoidhard striking against the extension limit stop.

The flexion valve 50 has increased flexion resistance during thestanding phase, in order to dampen the bending during the downwardmovement. Subsequently, the flexion valve 50 is slowly opened, in orderto make a flexion movement possible. In the swinging phase, the dampingremains low, in order to make extension assistance possible, if sodesired;

alternatively, the flexion damping may also be increased, as is providedin the region of the mid swinging phase. In the region of the terminalswinging phase, maximum flexion damping is again provided.

Shown in FIG. 12 are a circuit arrangement and a switching progressionthat can take place when steeply down an incline according to FIG. 11,if the pressure accumulator 23 is to be charged or if electrical energyis to be generated in the generator mode of the pump 21. The switchingvalve 60 is moved into the position A during the standing phase, inorder that energy can be fed to the accumulator 23. It is advisable thatthis should only take place whenever the accumulator pressure does notexceed the piston pressure as a result. Should this be the case, thecircuit diagram according to FIG. 11 would be applicable.

As a departure from FIG. 11, in the control according to FIG. 12 theextension valve is already opened in the terminal standing phase and theextension damping is reduced. The extension valve remains open over theentire initial swinging phase and is only closed again in the midswinging phase, in order to increase the extension damping in order thata hard strike is avoided at the end of the swinging phase. The flexionvalve remains open over the entire sequence of movements, in order todirect energy into the accumulator 23. The position of the valve shouldbe adapted to the difference in pressure between the accumulator 23 andthe piston. If the accumulator 23 is empty, the flexion valve 50 may beset in such a way that there is greater flexion damping. The flexiondamping should likewise be kept low in the swinging phase, in order tomake extension assistance possible, if so desired. The switching valve290 is opened during the standing phase, in order that the oil flowthrough the generator can be used for obtaining power. The valve 28remains closed. In the extension phase, the valve 290 is closed, inorder that extension assistance by the pressure accumulator 23 can bemade possible.

Shown in FIG. 13 is a timing diagram for a gait cycle in which a kneeangle KA is represented over time t. On account of the initial standingphase flexion, the knee angle KA is greater than 0° at the beginning ofthe gait cycle, that is to say when the heel touches down, known as the“heel strike”; it remains constant at 0° over the subsequent standingphase portion, until it increases after about 1.1 s. The knee angle KAincreases further after the end of the standing phase, known as the “toeoff”, up to a maximum bending of about 55° at t=1.35 s. After reachingthe maximum knee angle KA, a reversal of the movement takes place; thelower leg component is moved forward, so that the knee angle KA isreduced again on account of the extension movement, and at the end ofthe swinging phase, with the maximum or approximately maximumstretching, ends with a knee angle KA at 0°. As a departure from therepresentation in the other figures, the knee angle KA in FIG. 13 isdenoted by 0° in the stretched position.

FIG. 13 also reveals that an assisting bending moment FM is appliedimmediately before the bending. It can be seen from the knee angleprogression that the bending moment FM is not sufficient to bring aboutthe bending of the knee; rather, the level of the bending moment FM ischosen such that only assistance for bending by the user is provided,and bending is not brought about independently. This is evident from thefact that the knee angle KA remains unchanged over the entire timeperiod of the maximum bending moment FM. Already before the beginning ofthe bending, that is to say changing of the knee angle in the directionof the bending of the knee, the level of the bending moment FM isreduced, in order to avoid that the knee joint bends too easily, whichwould have inadequate stability of the knee joint as a consequence. Theonly temporary application of the bending moment has the advantage thatless energy has to be provided. Likewise, the knee joint remainspredominantly without bending assistance during the standing phase, sothat increased security against unwanted bending is ensured. Theassistance, which can be understood as reduction of the initiatingmoment for bending, allows a stable set-up to be chosen, so that anincreased degree of standing stability can be provided, without thisleading to an increased strain on the patient as a result of the secureset-up, that is to say the assignment of the individual components toone another.

After the “toe off”, that is to say at about t=1.2 s, there is no longeran assisting bending moment; rather, an extension moment EM is applied,acting as flexion damping and preventing excessive bending of the kneejoint. Instead of active application of an extension moment EM, purelypassive damping may also take place; it is likewise possible that energyis drawn from the system by conversion for the damping, so that theenergy required for the application of a bending moment can be at leastpartially returned. If a stretching moment EM is applied, the phase inwhich a stretching moment EM is applied is ended before completestretching of the knee joint.

It is possible and intended that the energy remains applied even beyondthe initiation of the movement, either at the same level or at a reducedlevel, in order to assist the user in the movement. The relatively lowlevel of supplied energy prolongs the possible times of use withoutmaintenance.

In the diagram according to FIG. 13, the applied power P and also theperformed work

W are also plotted. The power P supplied by motor increases at thebeginning of the bending of the knee; after the “toe off”, there is anexcess of power, that is to say no motor power has to be supplied. Afterreaching the maximum knee angle, power is required again for extension,so that the power P becomes positive again.

Control such as that described on the basis of FIG. 13 can be carriedout not only with a hydraulic drive device; it is similarly intendedthat the bending and stretching moments are applied directly by way ofan electric motor, possibly with a suitable gear mechanism interposed.For damping the movement at the end, the motor may be changed over togenerator mode, it being possible for the electrical energy generated tobe stored in a storage battery or capacitor, in order to be able to callupon it at the appropriate time.

1. An orthotic or prosthetic joint device with an upper part and a lowerpart, arranged in an articulated manner thereon, and also fasteningdevices for securing the joint device on a user, with at least onehydraulic unit between the upper part and the lower part, whichhydraulic unit has a piston, which is movable in a housing with anextension chamber and a flexion chamber, is coupled to the upper part orthe lower part and is assigned a pressure providing device with a pumpand a pressure accumulator, by way of which a pressure is applied to thepiston while being controlled by a control device, characterized in thatthe pressure accumulator can be coupled to the pump in a driving way. 2.The joint device as claimed in claim 1, wherein the pump can be operatedin generator mode.
 3. The joint device as claimed in claim 1, whereinthe hydraulic fluid can be fed from the pressure accumulator though thepump to the hydraulic unit.
 4. The joint device of claim 1, wherein thepump has a variable delivery volume, which can be adapted to thepressure in the pressure accumulator.
 5. The joint device of claim 1,wherein the pressure accumulator is coupled to the hydraulic unitexclusively by way of a feedthrough through the pump.
 6. The jointdevice of claim 1, wherein a device for detecting the joint angle, theabsolute angle, the axial force acting on the upper part or lower part,the joint moment and/or the moments acting on a distal connectioncomponent is assigned to the control device.
 7. The joint device ofclaim 1, wherein it is designed as a prosthetic knee joint or anorthotic knee joint.
 8. The joint device of claim 1, wherein thepressure accumulator is assigned at least one valve unit for the meteredintroduction or removal of the hydraulic fluid.
 9. The joint device ofclaim 1, wherein the pump and the hydraulic unit can be connected to thepressure accumulator in a pressure-admitting manner.
 10. The jointdevice of claim 1, wherein multiple pressure accumulators with differentpressure levels and/or volumes are provided.
 11. A method forcontrolling an orthotic of a prosthetic knee joint device with an upperpart and a lower part arranged in an articulated manner thereon,fastening devices for securing the joint device on a user and also adrive device for applying a moment to the knee joint device,characterized in that, before the bending or stretching, a bendingmoment or stretching moment that lies below the level that leads tobending or stretching is applied to the knee joint device.
 12. Themethod as claimed in claim 11, wherein the bending moment is reducedwhen the knee joint device is bent or before the knee joint device isbent.
 13. The method as claimed in claim 11 wherein the bending momentis applied in a time period before the bending that is between 5% and40% of the duration of a gait cycle, in particular between 5% and 20% ofa gait cycle.
 14. The method as claimed in claim 11, wherein a bendingmoment of a varying degree is provided in dependence on the walkingsituation.
 15. The method as claimed claim 11, wherein a bending momentof a varying degree is provided in dependence on the prosthesis set-up.16. The method as claimed in claim 11, wherein the bending moment isapplied up to a predetermined, ascertained bending angle.
 17. The methodas claimed in claim 11, wherein after the introduction of the bendingmoment, passive damping takes place or the pump is operated in generatormode.
 18. The method as claimed in, claim 11, wherein the application ofa bending or stretching moment is maintained beyond the beginning of thebending or stretching movement.
 19. The method as claimed in claim 11,wherein a reduction of the stretching moment is initiated beforereaching the stretching limit stop.
 20. The method as claimed in claim11, wherein in the case of alternating climbing of stairs, the pressureproviding device applies the stretching moment in such a way that theforce vector is kept ahead of the pivot axis of the knee joint. 21-22.(canceled)